Process of depriving electric devices of occluded gases



Aug. 9, 1932.

B. VAN DER POL 1,871,017

PROCESS OF DERRIVING ELECTRIC DEVICES OF OCCLUDED GASES Filed March 30, 1929 awumfoz BALTHASAR van der POL Patented Aug. 9, 1932 7 a UNITED BALTHASAR'VAN DER, POL, or nrnnnovnn, nET nnL nns, Assrenon TO nAnIo con- PORATION or AMERICA, or new "roan; n. Y., A conronarron or DELAWARE.

PROCESS OF DEPRIVING ELECTRIG DEVICES O CGLUDED GASES Application filed March 30, 1929, Serial No. 351,200, and in the Netherlands March 30, 1928.

The invention concerns a process of depriving electric devices of occluded gases, more particularly a process in which use is made of a bombardment by electrons.

The invention has for its object to improve upon such a process, more particularly to provide a better method of degasifying parts which under ordinary conditions cannot easily be reached by the electrons.

According to the invention, this object is attained bycausing the paths followed by the electrons, when electric devices are deprived of occluded gases by means of electric bombardment, to be influenced by a magnetic field.

The invention will be explained more fully with reference to the accompanying drawing which represents a discharge tube, which can be freed from occluded gases with the aid of the process constituting the subject matter of the present invention.

In the drawing, a discharge tube 1 comprises an incandescent cathode 2 and a cylindrical anode 3 which is secured to a stem 6 with'the aid of supporting rods 4 and a collar 5, the leading-in wires of the cathode being taken out through a stem 7.

For depriving such a device of occluded gases one usually proceeds as follows: After the highest possible vacuum has been obtained by pumping (the pump may be connected to the tube at 9), the incandescent cathode is heated by an electric current while the anode is given a positive potential with relation to the cathode. Under the influence of the electric field produced, the electrons emitted by the cathode 2, move to the anode and heat the latter by impinging thereon, due to which the gases occluded in the anode are liberated so that they. can be removed by pumping.

The process, however, has the disadvantage that some metal parts, for example the supporting rods 4, are struck by only few electrons, so that they are poorly freed from occluded gases.

According to the invention, this disad: vantage is remedied by causing the electrons to move under the influence of a magnetic field to parts which are to be deprived of occluded gases. As diagrammatically shown 7 in the drawing, this can be realized with the aid of a coil- 8 which is so arranged thatv the magnetic lines of force run in the'direction from the cathode to the anode. The force exerted by this magnetic field on the electrons i moving in a direction perpendicular to the surface of drawing, is normal to the direction in which the electrons move andalso to the direction of the lines of force. It'fis evident that thus these electrons canbe dienvelope enclosing an electron emitting oath ode, an anode and a metal part normallyoutside the electron stream from said cathode to sald anode, which comprises establishing an electron stream from said cathode to said,

anode during the evacuation of said envelope, and subjecting said stream to a mag netic field of a direction and magnitude sufficient to deflect said stream from its normal course and cause it to impinge on and thereby denude said metal part of deleterious gases. 2. The method of exhausting an electron discharge device comprising an evacuated envelope enclosing an electron emitting cathode and an anode having a metal support which comprises establishing an electron stream from said cathode to said anode during the evacuation of said envelope, and subjecting said stream to a magnetic field of a direction and magnitude suhicient to deflect said stream from its normal course and cause it to impinge on and thereby denude said metal support of deleterious gases.

8. The method of exhausting an electron discharge device comprising an evacuated envelope enclosing an electron emitting cathode, an anode, and metal parts adjacent said anode but normally outside the electron stream from said cathode to said anode,

which comprises establishing an electron stream from said cathode to said anode during the'evacuation of said envelope, applying to said metal parts a positive potential no greater than that of said anode, and subjeoting saidstream to a magnetic field of a direction and magnitlide si flicient to deflect said stream from lts normal course and cause it to mpinge on and' hereby de ude a d metal parts of deleterious gases.

' BALTI-IASAR vim DER POL. 

